Typically, ground holes are drilled by drill rigs in order to produce a hole for use in mining or construction. In some instances, these holes are drilled by a drill rig controlled by a user who plans and executes the drilling process.
The operation of a drill rig requires the consideration of many variables before the user can successfully initiate and complete the drilling operation. These variables include ground or surface conditions, the geological status of the area, environmental conditions, the intended purpose of the hole and the inherent limitations of the drilling equipment. In some situations, there may not be enough information at the initial stage for the user to make an appropriate or informed decision in other words once drilling has commenced, the user generally makes appropriate adjustments in order to successfully drill the hole.
In situations such as mining or construction, it may be necessary to drill many holes in a large geographic area. Typically, where the user is required to make appropriate adjustments in order to successfully drill a hole, the drilling process may be inefficient, expensive and time consuming.
In open mining operations, for example, there is a need to balance the speed of drilling holes against the stability of the hole formed. When preparing the ground for blasting there may be literally hundreds of holes required with drilling, which may take a number of days to drill. There may also be some time before the holes are eventually filled with explosives for blasting. In the event of materials re-entering the holes, the effectiveness of the subsequent blast is reduced.
Where significant hole re-filling occurs there can be a need to re-drill such holes. In all ground filling, it is usual for a collar of drilled material to form around the drill string creating the hole. The stability of such a collar is dependent on many factors—geology, waste chip size, etc. In open pit mining an additional factor is that the surface being drilled may be disturbed or broken, such as from earlier blasting and the subsequent removal of blast material. Thus, it is critical that a stable collar is formed so that backfilling of the hole during drilling for post drilling is minimized or avoided.